I had an article in
Pyramid #3/88
dealing with abandoned nuclear reactors and other sources of
radioactive fun.

I'd been reading about nuclear procedures and accidents for
another project, and the post-apocalyptic theme gave me an opportunity
to explore a reasonably obscure, not to say speculative, branch of
knowledge. Nobody has abandoned a nuclear plant completely, unless
it had already gone badly wrong: even the Chernobyl site is monitored,
and occasional remedial work is done there.

The short version: if you are abandoning a nuclear reactor, or
vehicle, in a hurry, that is on a timescale involving less than months
or years of careful and expensive preparation, you probably won't want
to come back.

I was amazed to find out how shallow the Yucca Mountain repository
turned out to be (only 50m down!). Putting the site on a major fault
line too smacks of carelessness. Or, of course, conspiracy.

The feel of an abandoned, irradiated site is very like that of an
empty city, but it may well be one that's in better shape than others
in the post-apocalyptic world: after all, it hasn't been effectively
scavenged. Some windows have cracked, some buildings are sloughing off
pieces as the wind and rain take their toll, but there hasn't been
much plant or animal damage as you'd expect. In a
post-apocalyptic game, player characters who remember the old days may
well have flashbacks to the way things used to be. The photos on
Elena Filatova's hoax site (actually taken
on official tours or in other locations, or used uncredited from other
sources) give a good idea of the ambience.

Birds, which have a higher radiation tolerance than most other life
forms, may move into the niches normally occupied by other animals,
similarly to the way they get into a ground-scavenging role on some
Australian islands where rats have never been imported.

How else can this material be used, apart from the "end of
civilisation" scenario?

An economic failure, especially combined with scientifically
illiterate politicians (perish the thought), might well lead to
facilities being abandoned rather than decommissioned. Shortly
afterwards, things go badly wrong, but there's a civil infrastructure
to try to deal with the problems.

A reactor powering a base on another planet might well be abandoned
when the mission is done, though one would hope it could be got into
a safely stable state.

If nuclear warheads are stolen but not used, perhaps traded between
illegal groups in return for substantial other assets, they'll decay
to unusability within a few years, though they'd still be useful for
construction of new devices. (Personally I regard the R-bomb, one of
the several things described as a "dirty bomb", as much more of a
threat than a nuclear detonation: wrap radioactive fragments or dust
round a substantial explosive core, and you have all the terror of
radiation release, but a far less technically demanding job to produce
it than you would if you were trying to set off a warhead.)

When you say 'birds', does that genuinely mean all birds, or is it a case of someone did the tolerance experiments on lab animals such as pigeons and zebra finches, then extrapolated it to all life forms with feathers?

I don't know how widely it's been tested, but certainly there are wild birds nesting in the fiercely radioactive buildings of Chernobyl and not apparently taking harm from it; some of them have slightly malformed tail feathers, but they aren't being out-bred by non-malformed birds.

I wonder if it is a situation like the Mexican/Central American birds that are lining their nests with the 'fluff' from discarded cigarette butts? Advantage - the nests have far fewer parasites 'cos of the nicotine, so you raise more chicks. Disadvantage - the chicks start showing signs of nicotine related disorders later in life.

Yes, there's that, but the small mammals for example do show clear evidence of harm from mutation, and the decay organisms are so thoroughly disrupted that corpses just lie in place with minimal rotting until something eats them.

There's lots of weird stuff round Chernobyl. The pine forest that turned red and died, but is still mostly standing (no decay organisms) is a fine one. You have read the Charlie Stross story about it, I presume?